HATCHES is a collection of data for use in radiochemical modeling work. The data base
includes thermodynamic data (the log formation constant and the enthalpy of formation for the
chemical species) for the actinides U, Th, Pu, Np, Am and Cm and for fission products including Cs,
Ru, Tc and Sr.

APPLICATION OF THE DATA

HATCHES was created using the Microsoft® Access Software on a MS Windows computer.
It consists of the database and a MS Access runtime version and is, therefore, independent of other
software. The database is secured and cannot be modified. Since it is an Access database, the use of
HATCHES is straightforward. Output options are provided to convert the contents of the database
into the format required by the PICKER/PHREEQE programs or to create the components of a data0
file for use with the EQ3/6 program.

The thermodynamic constants (stability constants and solubility products) included in
HATCHES were selected as the best data available at the present time, and the database is
continuously being updated as improved data become available. In a number of cases, when there was
evidence for the existence of a species but no good experimentally derived constants were found,
estimated data were included. Throughout the compilation of HATCHES, every effort was made to
produce a self-consistent database. Each entry includes a full description of the source of the data,
together with details of any calculations that were performed on the data, (e.g. correction to zero ionic
strength). In addition, each entry includes all associated input information required by the PHREEQE
code (e.g. charge, stoichiometry, operational valency) together with any comments concerning the
validity of the data.

SOURCE AND SCOPE OF DATA

At present the database has only been compiled for use at 25 degrees C. In a limited number
of cases, the enthalpy data required for calculations at other temperatures are included; but these data
were not used at Harwell. Included are statistical error analyses of the measurements. Complete
validation of the HATCHES data would be an impossible task; however, limited validation is achieved
each time a dataset is used to successfully model experimental results. It is hoped that the wider use
of HATCHES, to model a variety of different systems, will result in an increased amount of
"validated" data. The authors would, therefore, welcome any feedback from modelers using
HATCHES concerning the validity of the data.

7. DISCUSSION OF THE DATA RETRIEVAL PROGRAM

The software runs under Microsoft Windows. To retrieve data files, the proprietary database
software ACCESS 97 is not required. The distributed package contains the source and executable
image of programs PHREEQE and PICKER as part of the package received from Harwell, but these
programs were not tested by either the NEA or RSICC.

The PICKER application extracts a part of the PHREEQE database. One hundred master
species can be chosen as components of reactions. Programs are available to convert data to formats
compatible with PHREEQE-base, CHEQMATE-based, and EQ3/6-based geochemical modeling
codes. Some data were converted and are included with the package.